Lightning’s big bro connects Apple’s headset to its battery.

Apple’s Vision Pro battery pack is hiding the final boss of Lightning cables::The Vision Pro’s battery connector is removable once you press the eject button, and it uses a 12-pin connector that looks like a wider version of a Lightning cable.

  • @abhibeckertEnglish
    -6•10 months ago

    I think it’s reasonable.

    First of all they didn’t want to put a battery on the headset. Fair enough, even without a battery it’s heavier than most headsets.

    That decision means the cable doesn’t just need to provide average power consumption, it also needs to be able to handle peak power consumption. It seems reasonable that the headset has similar peak power to a Mac Mini - which has a 185 Watt power supply.

    USB can provide up to 240 Watts, however it needs relatively high voltage to do that over thin cables permitted in the USB specification. 48 Volts for 240 Watt power delivery and 20 Volts for 100 Watts.

    Vision Pro is only 13 Volts - which means that cable almost certainly has thicker wires than a standard USB cable. If you tried to power a Vision Pro over a standards compliant thin USB wires it would likely be a fire risk at only 13 Volts.

    Apple could solve that by using 48 Volts… but then they’d have to convert 48V down to 13V… and they need to do it with very light weight and small components. Those conversions are not free, especially with DC power. It might even be that the conversion is so inefficient that you need more than 240 Watts to power the headset.

    But even if 240 W is enough (it probably is), it would also reduce battery life. And battery life is already an area where the headset isn’t really good enough. So, in summary, yeah I do think it’s reasonable to use a proprietary power cable. This headset is just too close to the technical capabilities of a USB cable.

    Worse… a lot of USB cables aren’t even compliant with the specification. You could burn someone’s house down if the cable is non-compliant.

    • @apemintEnglish
      32•10 months ago

      There’s nothing reasonable about these assumptions.

      There’s no way the VisionPro gets even close to 100W. Why? Because heat dissipation. The vast majority of power drawn by semiconductors is dissipated as heat and, in a device that’s strapped to someone’s face, there’s simply no way to dissipate hundreds of watts.

      Also, knowing the battery pack size and battery life, it’s easy to guesstimate the power consumption.

      “The Apple Vision Pro provides approximately 2 hours of battery life. Based on its size, the internal battery capacity is estimated to be within 20,000mAh (74Wh), resulting in an overall power consumption of around 30W.”

      Even if we assume the double of that 30W, it’s well within USB-C standards.

      • @[email protected]English
        8•10 months ago

        Very good explanation. If usb-c is good enough for a MacBook, it’s definitely good enough for a small headset - no excuses!

    • @XeroxCoolEnglish
      9•10 months ago

      I think you’re confusing volts and amps. Higher amperage wire has thicker copper conductors. Higher voltage wire has better insulation and some standards about how far connections have to sit. Raising voltage increases the chance of sparks, but amperage is what runs into heat problems with modern insulation. Wattage (power) is simply Volts x Amps. To get higher wattage, you can increase volts or amps (or both of course), depending on what materials and devices you have available. The whole point of going to higher voltages in usb is to carry more power without making the cables thicker and without overheating thin wires.

      Most circuit boards are 5v. I’m sure Apple already has a converter on board. Also, the DC conversion problem is outdated - both on difficulty and inefficiency. Solid state devices are able to switch power on and off at a frequency to make an onboard converter coil work with the same efficiency as AC. The little extra heat lost from the switchers is made up for by not wasting time/energy on phase cycling. Check out “buck buck” converters.

      Volts, amps, and watts are all different units and do not interchange. They are related, but serve different functions.

      Fun fact: powerlines all use much higher voltages on the transmission wires than what you have in your house. The lower amperage (but same wattage) uses less material for wiring and loses less energy as heat along the way. North American houses have 120v, the transformers on the nearest telephone poles drop it from 440v, and the overhead lines are 440,000v with various possibilities in between substations

    • @iarigbyEnglish
      -2•10 months ago

      Thank you for the explanation